1. Field of the Invention
This invention relates generally to an apparatus and method for applying material, and more particularly to an apparatus and method for applying discrete lengths of a material to a moving web; such as, for example, applying a discrete length of elastic material to a disposable diaper bottom cover film.
2. Description of the Prior Art
Elastic material has been used in a variety of goods to provide an area that can be expanded or contracted to better fit the object on which the goods are placed. Examples of apparels on which elastic have been used are underwear, intimate wear, swimming wear, pants, skirts, jackets, fitted sheets, lab uniforms, diapers, and surgical garments, food related applications, such as porous holders/filters, i.e., for lemons. It also may be used to apply an elastic band around other articles, such as trash bags.
Typically, the elastic material has been secured to the goods by either stitching, heat sealing or an adhesive. Recently, the H. B. Fuller Company, Saint Paul, Minn., the assignee of the present application, developed a Fullastic.TM. material that is a pressure sensitive elastic that can replace sewn, heat-sealed or glued elastic in single use items such as disposable diapers, non-woven garments, surgical caps and drapes. The Fullastic.TM. material may also be used on reusable garments under certain circumstances, such as garments that can be washed in cold water. The Fullastic.TM. material is disclosed in U.S. Pat. No. 4,259,220 issued on Mar. 31, 1981 and U.S. Pat. No. 4,418,123 issued on Nov. 29, 1983. U.S. Pat. No. 4,259,220 discloses 2 methods of applying the pressure sensitive adhesive to a continuous substrate. The first method applies the pressure sensitive adhesive in a stretched state to a continuous substrate. The second method shows the pressure sensitive adhesive being applied in an unstretched state to a pregathered substrate. The Fullastic.TM. material can also be referred to as a self-adhering elastic, as well as a pressure sensitive adhesive.
One example of applying an elastic material to a diaper is disclosed U.S. Pat. No. 4,081,301 by Mr. Kenneth Buell. The patent discloses a method of applying a discrete, stretched, adhesively coated elastic material to predetermined portions of a disposable product at specified distances from the edge of the diaper. A method of applying discrete lengths of an elastic material, in an unstretched state, to a moving web is disclosed in U.S. Pat. No. 4,397,704 issued to Richard H. Frick. A continuous strip of adhesively coated material is severed into discrete lengths and transferred to a moving web. It is necessary to adhesively coat the elastic before applying it to the web material. In addition, if two separate, discrete lengths of material are to be applied in a space relationship to one another, it would be necessary for two sources of elastic material to be available. If the source of elastic material is an extruder, it would therefore be necessary to have two extruders available. This would increase the capital expenditures that are necessary to set up a manufacturing line.
U.S. Pat. No. 4,379,016 assigned to Winkler and Dunnebier discloses a method of spraying elastic strips onto a web of material used for making diapers. However, this patent provides for the spraying of the elastic material over the entire length of sections of the web. The elastic material is sprayed into the grooves of the web. Therefore, the elastic strip is adhered to the corrugated substrate in an unstretched state when the web is also gathered up. Further, an embossing roller having a tooth-like gear surface is used to form a multiplicity of fine folds in the web. Such a method and apparatus would again require two applicators to form two spaced part elastic members on a moving substrate.
The present invention addresses the problems associated with the prior art devices and provides for an apparatus and method for transferring a material, such as a self-adhering elastic extruded from a single source, and separating this extruded material into two distinct segments at a transfer point.